Considerations in the Repair and Replacement of Historic Windows

April 29, 2011
Publication: Building Enclosure Sustainability Symposium 2011, Integrating Design & Building Practices: Proceedings of the 2nd Symposium p 337-353

Abstract: Existing buildings represent an opportunity for environmentally responsible design due to their tremendous embodied energy and, in many cases, their proven longevity. However, renovations to existing buildings, especially those with historic significance, must take that significance into account rather than simply “modernizing” the building with new materials and systems. Windows are often a prime candidate for energy retrofit due to their relatively large contribution to overall heat loss/gain for the building, but at the same time can be one of the significant features of the building making their replacement unacceptable from a preservation standpoint. Further, outright replacement of windows does not always result in a reduction of heating and cooling loads. This paper presents criteria for consideration when dealing with historic windows, reviews investigation and testing methods, shows examples of energy modeling techniques and discusses window repair and replacement options.